Why can't we just update to ghc 7.0.4 for now? Nothing will break,
look at the bugfixes:
http://haskell.org/ghc/docs/7.0.4/html/users_guide/release-7-0-3.html
BTW Fedora is doing a better job with Haskell then Arch now. they
updated to 7.0.4 and are supporting a lot more packages. And now we
are dropping packages.
I think haskell packages are indeed a bit trickier then normal
c/c++/python/etc libraries and packages, since their dependencies
seems to be much stronger. And keep in mind "rolling release" does not
mean "unstable" or "testing", it just means that we don't have
releases but the system must always work and must be stable.
"Bleeding edge" in an unfortunate expression.
It we are going to be a "experimental" with 7.2.2 (which I think it's
a mistake) we have to have a mechanism to ensure that at least a set
of important packages used in production will never break, that there
are quite a few of them.